An injection stretch blow molding apparatus called a 1.5-stage one, has been known as a blow molding apparatus in which a preform is disposed in a blow cavity mold, and the preform is blow-molded to form a hollow container (see, for example, Patent Document 1).
Such a blow molding apparatus is equipped with a transport apparatus for continuously transporting the preforms. The transport apparatus described in Patent Document 1, for example, has a plurality of sprockets, a plurality of transport members engageable with the plurality of sprockets for holding the preforms, and a guide rail for guiding the transport members along a transport direction.
In the above blow molding apparatus provided with such a transport apparatus, when a flat container of a nearly circular shape in a plan view or an in-mold labeled container, for example, is to be formed as a hollow container, it is necessary to align the respective preforms circumferentially in a constant direction and arrange them in a blow mold. Various transport apparatuses equipped with mechanisms for aligning the preforms, which are continuously transported, in a constant direction have been proposed (see, for example, Patent Document: 2).